In modern computing practice, data centers have become more important than individual machines. A user's desktop may be hosted on the network and accessed via a minimalized client device. On the server side, individual servers and appliances have been replaced by large racks of identical servers that are provisioned with virtual machines (VMs) providing the individual functions, controlled by a hypervisor.
In some cases, a virtualized network may also include network function virtualization (NFV), which provides certain network functions as virtual appliances. These functions may be referred to as virtual network functions (VNFs). Other data centers may be based on software-defined networking (SDN), or other similar data center technologies.